Monday, July 6, 2015

Whither methyl iodide?

I read with interest the business article on fumigants (C&EN, June 8, page 18). I find it hard to believe that the California State Legislature would approve methyl iodide as a crop fumigant. I base this on both its potential toxicity to farmworkers (it is a powerful alkylating agent) and on the lack of scientific studies that may turn up currently unknown oncogenicity, genotoxicity, and neurotoxicity.

Could the Environmental Protection Agency focus some of its attention away from carbon dioxide long enough to fund this important work? Does the $2.6 billion strawberry crop hold any sway?

Geoff LindsayRidgecrest, Calif.

I don't know the science around methyl iodide, but it seems to me that it would be a bit less hazardous to farmworkers than methyl bromide (from a volatility perspective.) That said, I'd expect it to be no less toxic to them, if exposed to enough. Surely there must be a safer alternative?

3 comments:

Another alternative is propargyl bromide - not nice if you ask me. But at least you won't inadvertently poison yourself because propargyl bromide smell is revolting. They have been adding odorant to methyl bromide, but apparently not enough.

There is interesting chapter in Gergel's "Excuse me Sir, Would You Like To Buy a Kilo of Isopropyl Bromide?" ftp://www.fourmilab.ch/pub/etexts/www/gergel/isopropyl_bromide.pdf

Apparently, the author nearly fatally poisoned himself with MeI, by manufacturing it on large scale in a poorly ventilated lab; MeI has creepy and rather profound neurotoxicity on chronic exposure. This later qualified him to testify as expert witness in lawsuits filed on behalf farmworkers killed with MeBr.